Research Suggests Cystic Fibrosis Is Two Diseases, Not One

A new study suggests that cystic fibrosis (CF) may not be one but in fact two separate diseases. One of these diseases affects several organs including the lungs, while the other does not affect the lungs or respiratory system at all.

A team of researchers from the University of Pittsburgh, the Mayo Clinic, Brigham and Women’s Hospital, and other member institutions of the North American Pancreatitis Study Group studied the disease and found nine variants in the CFTR gene linked to CF. This gene may lead to pancreatitis, male infertility, and sinusitis but spare the patient’s lungs.

CF patients inherit a severely distorted copy of the CFTR gene from each parent, which causes a dysfunctional CFR channel. This in turn causes abnormal secretion of sweat, mucus, tears, digestive enzymes, and semen leading to problems such as lung congestion and male infertility.

In particular, the researchers sought to understand why patients with pancreatitis do not have cystic fibrosis. Dr. David Whitcomb, chief of gastroenterology, hepatology and nutrition at Pitt School of Medicine, and his team uncovered evidence that CFTR gene mutations can cause two separate diseases. These are cystic fibrosis of the lungs and cystic fibrosis of the pancreas. The discovery can have significant implications in developing treatments for both diseases.

Dr. Whitcomb said, “New drugs can make the CFTR gene work better. If it is defective, medicines can compensate and make the protein work better, but they’ve never been tested before on pancreatitis, and that is the type of thing I’m excited about. We know what the problem is, and now we can start working on the solutions. This is the first time that there’‍s hope for patients and their descendants.”

Earlier this month the U.S. Food and Drug Administration (FDA) approved Boston-based Vertex Pharmaceuticals’ Kalydeco for the treatment of patients with the G551D mutation, a rare strain of cystic fibrosis. The drug showed potential for combination with other drugs for long-term treatment of CF patients. However, past drug combos like ivacaftor and lumacaftor, also manufactured by Vertex Pharmaceuticals, have given rise to mixed opinion in the scientific community as to their efficacy. Laboratory research suggests that the CF drug combination may interfere with the other’s function in treating the disease.